This proposal requests funds for the development of a new generation confocal microscope uniquely capable of ultraviolet (UV) as well as visible illumination and video-rate imaging. In Phase I, experiments will be conducted to determine the components and dimensions needed to correct for the longitudinal and lateral chromatic errors experienced with UV light. The longitudinal errors are to be corrected by incorporation of a second beam expander. The lateral errors are to be corrected by a proprietary optical system. These corrective measures will make the light path for the UV and visible beams congruent through the system to enable rapid interchanging of the excitation wavelengths or, in certain instances, allow simultaneous UV and visible excitation. Further objectives to be realized in Phase I are the construction and characterization of two-dimension scanning mechanisms capable of utilizing UV or visible wavelengths. The components, configurations and technologies devised in Phase I will be utilized in Phase II for the design and construction of functioning prototypes of this new generation of confocal systems. In this phase, optical platforms will be designed to be attached to various commercial microscopes greatly expanding the optical range and measurement speed of this new and exciting technology.